Auxiliary fuel tank



June 1947. c. 'L. JOHNSON AUXILIARY FUEL TANK 4 Sheets-Sheet 1 Filed May 12, 1944 INVENTOR. 5L AREA/5E L. JUH/VSJN AGENT June 3, 1947.

L. JOHNSON AUXILIARY FUEL TANK 4 Shets-Sheec 2 Filed May 12, 1944 June 3, 1947.

AUXILIARY FUEL TANK Filed May 12, 1944 4 Sheets-Sheet 5 105- lQ- i a? I 10s Z mmvroa CLARENCE L. .hHNMN 'AGENT c. L. JOHNSON 2,421,699

June 3, 1947. c. 1.. JOHNSON AUXILIARY FUEL TANK Filed Ma 12, 1944 4 Sheets-Sheet 4 (b) INT wme TANKS (c) WITHOUT TANKS (0) TIP WING TANKS L. him/50M ZLAHEMJE AGENT Patented June 3, 1947 Clarence L. "Johnson, Encil'l'offigtlifl, as's'sigrior t'o' Corporation, Burbank,

Lockheed 'Aircraft Galif.

wing ;ta-r'1ks have heretofore been constructed in name gtanksbaniie a'di ahtagously but 'ih' Zsdih'e' bases'arid' urid'er some conditions is "getuauy dje'rease'ii toawalueilesst an that which t ewmghas" without sii'ch external tanks. It has alsebeen disebvid that,'in genei'al, the drop- -a"iiiaif1 ed reafition in drag overt-hat which the sarhe tanks eause when suspended at an-intermediate portion of the wing span as has heretofore heen conventional practiee. Full advantage and benefit of the-additional fuel which may be carried-in suchexternal; droppable oriettisonable *wing tanks -'may thus 'be realized :by attaching them to the "wings in the "manner of the presentinvention.

It is, accordingly, an object of this inveiition p130 provide-an improved means for carrying a disposable auxiliary 'fuel load on *an airplane.

It is a further object to provide an improved method of attachment of'aneXternaI wingtank, bomb, or the like 'body, to the wing *of "an "airplalne.

These and 'other objects and features "of nov- Fe'lty :will beciimeevident hereinafter in the description which, together with the following diawings, illustrate fipreferfed emldodinierit's of the in- -vention.

Fig'iz" 1 is ajipl" "View showing the general a "arise "fit of th'e Wing tip tanks on an airerene.

elevation of the gefi'eia] unis airplane ggsub'stamga11y jeiivr tid ai d n hai n i al "H eed W ngs ian -h "Atfih n an esl;s z' i tanks} and ll, of i u ar 1: .5 ep ivn gent stream1-ined--profi1e, said tank heme-supported at a poirit below and substantially at the" tips. The tank-isfoi medaspest shown in Fig- 1111'84 with upper recess-2!] and sur iour ding ;-fa1tings and fillets Zljof; such shape as geflfeetiye- 1y to -merge the streamlined form of'the'tank into theendj contour of the Wing tip.

As bestshownin the Fpreferredetructure in Figures -3 and "4, the-fue1-tanks,f6-and :H are each suspended "frame wing tip by-"me'anspf a --conventiona1 bomb shackle mechanism as shown at 25. The 'bombshacklcarries a pair'of' pivotable -ho'oks*26 "and '21, the 'fing'ers of which reach through thespalir of U bolts 'or' 'clevises 72 B a'nd '29 whichare tui'n 'onnectd 'b'y suitable fmeans, such *as 4051 Welding, to internal tank bulkheads 3fl andF3-l. A horizontal Iihk32 eictenflsbetwee'n pivots 33 a'fid'34 if! the upwardly extendihgflever :portio'iis dfthe-shicklehdoks-26and 2"1 to=provide *for 'simultaneous pivotali'motion ofthe'said hooks 28 "and 21 Tfor simultaneous insertion or With- "dfawaIofthe hobkfingefs from then "shaped clevises 28 and 29. The said clevis''si'B 'aha fl -rest uponthe fing'ers of hooks '26 andZI at'points *eccentiic'ally positioned with respect to th hook ipivots 3'1 wand-38 so thatitlr sajiwhookw-under the 'turnin'g moment of "the "weight of the fuel tank, tend to open by clockwise angular rotation about the pivots 31 and 38 as viewed in Figur 3. A lever 35 extending laterally from the body of the hook 26 serves to resist the opening turning moment thus imposed upon the hooks 26 and 21, by the weight of the fuel tank and thus preventing the release of the clevises from the hooks by resting at its outer, end 39 against a cam surface 40 which is in turn pivotally supported at 4| in the body of the bomb shackle 25. A control lever 42 extends upward from the cam 45, and the downward force of the hook lever 35 acting eccentrically against the cam surface 40' tends to rotate the cam 40 and the lever 42 counterclockwise into locked engagement at 43 whereby normally the shackle hooks 25 and 21 are prevented from disengaging the clevises 28 and 29. However, forceful counter-clock rotation of the lever 42 suflicient to open the locking engagement at 43 and to move the cam surface 40 out of engagement with the end 39 of the lever 35 will allow lever 35 to drop and the fingers of the hooks 25 and 2'! to move out of engagement with the clevises 2B and 29, thus releasing the fuel tank from the 'wing tip. a

Provision is made for actuating the lever 42 from suitable control in the pilots compartment o from other suitable control stations in the airplane. This is accomplished by means of a bell crank 45 which is actuated by means of a Bourdon cable 46 which in turn passes through a suitable Bourdon housing 41' to a movabl control handle 49 in the pilots compartment in the airplane, all as best illustrated in Figures 1 and 5.

The hereinbefore described bomb shackle 25 is positioned to extend through a suitable longitudinal slot, as shown at 50 in Figure 4, in the lower skin surface of the wing tip and, for convenience of installation, is adapted to be suspended by av pair of links 63 and 54 from a pair of hooks 52 and 53 which are in turn carried on the outer end of pivotally supported levers 54 and 55. The said levers 54 and 55 are pivotally supported by suitable means such as by bolts or pins as shown at 56 which pass through suitable bushings in and adjacent the outer end of the wing beams 51 and 51'. Levers as shown at 58, extending rearwardly from the hooks 54 and 55,'normally are locked against rotation by means of latches 59' carried on spring actuated pawlsas shown at 60.

Operation'of the pivotal hooks 54 and 55 are accomplished by removing the hand hole covers provided at 6| and 52 in the upper skin surface of the wing tips and manually actuating the pawls 60 to latch or unlatch the hooks 54 and 55.

In the process of' installing the'wing tip tanks in place on the wing tips, the bomb shackle 25 is' usually first attached to the wing tank by engaging theshackle'hooks 26 and 21 with the tank clevises 28 and 29 and then the tank, together= with. thebomb shackle 25 is lifted by suitable means intoproper position below the wing tip with the bomb shackle .25 extending upward through the slot 50 and the shackle frame links 63 and 64 are then engaged by the finger 520i the shackle hooks 54 and 55. c

A pair of bumper strips '65 and 66 attached to the tank skin bear against the lower surface of the wing and serve to prevent lateral sway ofthe tank about the shackle support under flight conditions. .1

:. A supplementary. streamlining shroud mem- .ber. .61 is carried on the lower surface of the wing -shackle 25 which projects outward through the wing skin slot 50 into the air stream. Slots 68 and 69 are provided in the shroud 61 through which the fingers of the shackle hooks 26 and 2! and tank clevises 28 and 29 extend.

Referring now primarily to Figures 6 and 7, an alternative method of mounting the wing tanks in centered positions upon the wing tips is illustrated. p

The wing tanks which are of circular cross sectlon and of elongated streamlined shape, as hereinbefore described in connection with Figures 1, 2 and 4, are each provided with a recess 50 into which the curved end portion of the wing tip may extend. The wing tank is supported in a centered position with respect to the wing tip by means of a pair of intermediately positioned U shaped fillers or gusset members as shown at H and T2 in Figure 6 and at 12 in Figure 7. The gusset members are shaped With an inner contour adapted to fit the lateral curvature of the upper and lower surfaces of the wing tip along lines in the projected planes of the ends of the wing beams 73 and 14. The outer end of the gusset members H and 12 opposite the wing tips are angularly shaped to fit firmly into the V-shaped recess 10 in the wing tank. The before mentioned gusset members H and 12 are provided with thin layers of suitable padding material such as rubber or felt which are adapted to lie intermediate the inner surface contour of the gussets and the wing skin as shown at 15 to prevent scarring or damaging of the surface of the wing tip. The outer surfaces indicated at 1B and TI of the gusset members H and 12 carry attached to them thin streamlining shroud or fillet members I8 and 59 which encircle the wing tip and join together at their leading and trailing edges to form a fairing or filleting member whch smoothly merges the contours of the wing and the wing tank together.

The wing tank is held firmly in position and in alignment with the wing tip and against the gussets H and 12 by means of a conventional bomb shackle acting in tension and which is constructed and operated in a manner substantially the same as that hereinbefore described in' connection with Figures 3 and 4 except that it is positioned horizontally within the Wing tip. The shackle hooks 8i and 82 of the bomb shackle make connection with'the pair of tank clevises 83 and. 84 carried by the tank which in turn are attached at their inner ends in anysuitable manner such as by welding or riveting to apair of transverse tank bulkheads as shown at 85 and 86 in Figure 6. The inner end of the bomb shackle 85 is attached to the wing beams through a pair of end shackle frame links as shown at 81 and 88 by means of a pair'of eye bolts as best shown at 90 in Figure '7. The threaded shanks of the eye bolts 90 make sliding fits through holes in suitable angle plates I50 which are in turn'attached to the webs of the wing beams 13 and 14. The

'eye bolts are provided with suitable means such as wing nuts l6! threaded on the ends thereof for tensile adjustments.

Tightening of the wing nuts llll on the eye bolts 98 serve, by transmitting tension through the bomb shackle, to draw the wing tanks into firm engagement and position against the wing tips as determined bythe intermediate gussets H p and. 12.

Release of the wing tanks from the shackles is accomplished in a similar manner to that hereinbefore described in connection with Figures 3 and 5. A bell crank [05 pivotally supportedeupon an angle clip I06 extending from the inner surface 7 the preferred ones from an aerodynamic consideration, the construction of Figures 1 and 2 are the preferred ones insofar as the 'mechanicalland structural considerations are concerned;

For convenience the present invention has been illustrated and described 'hereinbefore as a means and method for more efliciently carrying auxiliary, jettisonable, or droppable wing tanks to be employed to carry supplementary fuel for the purpose of extending the operating rangeof an airplane. This invention however is to be understood as not limited to the carrying of fuel tanks but is to 'be understood to be equally applicable to the carryin of any other substance orbody which may be formed or contained in similar containers or shapes such as, for example, a bomb.

Insofar as the broad aspects of the invention detachably supported from or on the wings and they may be either centered with or dependent from the wing tips. The tanks also need not be exactly cylindrical in cross section as herein illustrated, but may be elliptical, or even rectangular in section, so long as they are properly streamlined With respect to their longitudinal axis and are also reasonably Wel1 faired into the wing tip surface contour.

It is to be understood therefore, that the foregoing is not to be limited but may include any and all forms of methods and apparatus which are included within the scope of the claims.

I claim:

1. In combination in an airplane, a wing, and separate jettisonable external containers of streamlined form having a maximum section of substantially greater thickness than and positioned in substantial parallelism with the maximum thickness of the tips of the wing, said external containers being.positioned adjacent the wing tips and having their axes disposed substantially parallel to the normal line of flight of said airplane, quick detachable means for releasing said container from the airplane while in flight, and means associated with said wing tips and containers adapted to merge with the containers whereby to house the quick detachable means and to provide fairings conducive to streamlined airflow around the point of attachment between the container and the wing tip.

2. In combination in an airplane, a wing, and a separate jettisona-ble external tank of streamlined form having a maximum diameter substantially greater than the thickness of the wing adjacent thereto, said tank being supported in substantial axial parallelism with the line of flightof the airplane and adjoinment with the tip of said wing, the surface contour of said wing tip and said tank being in substantial mergence.

3. In combination in an airplane, a wing, and a separate jettisonable external tank of elongated streamlined form supported in substantial axial parallelism with the chord and adjoinment with the tip of said wing, the surface contour of said'wing tip and said tank being faired into substantial mergence and quick detachable means actuable from a control station in said airplane for releasing said tank from said wing tip while in flight. r

* 4. Apparatus in accordance with claim 2 in which the tank is supported in substantially centered ,position'with respect to the chord plane of the wing tip,

5. Apparatus in accordance with claim 2-in which the tank is supported in a substantially dependent position with respect to and adjacent to the wing tip.

6. Apparatus in accordance with claim 3 in which the tank is supported in substantially centered position with respect to the chord plane of the wing tip.

7. Apparatus in accordance with claim 3 in which the tank is supported in a substantially dependent position with respect to and adjacent to the wing tip.

CLARENCE L. JOHNSON.-

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date,

1,996,281 Dolan Apr. '2, 1935 1,685,458 Lidback Sept. 25, 1928 2,105,307 Akerman Jan. 11, 1938 1,865,749 Fleet July 5, 1932 2,074,201 Bechereau Mar. 16, 1937 2,375,423 Lobelle May 8, 1945 2,375,858 Makaroff June 20, 1942 

